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A CO2 bridged photocatalytic interface between a nickel metal–organic framework and ruthenium pyridine for high-efficiency photoreduction of diluted CO2.

An acylamide-functionalized metal–organic framework has been synthesized via a solvothermal reaction and its proton conductivity is increased by nearly two orders of magnitude after the removal of guest DMA molecules.

Constructing high-quality white organic light-emitting diodes (WOLEDs) remains a big challenge because of high demands on the electroluminescence (EL) performance including high efficiency, excellent spectral stability, and low roll-off simultaneously. To achieve effective energy transfer and trap-assisted recombination in the emissive layer, herein, four Ir(III) phosphors, namely

Three new cucurbit[6]uril-based metal–organic rotaxane networks functionalized by a sulfonic group (–SO3H) have been designed and synthesized.

Two new transition metal–organic frameworks (CUST-751 and CUST-752) have been designed and synthesized, which can be used as multiresponsive fluorescence sensors to detect Fe3+ and Cr2O72−. Moreover, CUST-751 also can detect TNP.

An unprecedented fully reduced {MoV60} POM served as a cheap and robust molecular light-absorber model possessing wide light absorption and was applied to build a co-sensitized solar cell photoelectronic device.

This highlight focuses on the strategies to improve the photocatalytic reduction of low-concentration CO2 by MOF materials, including the modification of MOF skeletons and the preparation of MOF composites or MOF derivatives. It will provide insights into the rational design of heterogeneous catalysts to achieve efficient reduction of low-concentration CO2.

A POMOF with [W10O32]4− and mononuclear cobalt clusters as connecting nodes, which can be used as a photocatalyst to reduce low concentrations of CO2 in flue gas to generate syngas.

Photocatalytic carbon dioxide reduction (CO2RR) is considered to be a promising sustainable and clean approach to solve environmental issues. Polyoxometalates (POMs), with advantages in fast, reversible, and stepwise multiple-electron transfer without changing their structures, have been promising catalysts in various redox reactions. However, their performance is often restricted by poor thermal or chemical stability. In this work, two transition-metal-modified vanadoborate clusters, [Co(en)2]6[V12B18O54(OH)6]·17H2O (V12B18-Co) and [Ni(en)2]6[V12B18O54(OH)6]·17H2O (V12B18-Ni), are reported for photocatalytic CO2 reduction. V12B18-Co and V12B18-Ni can preserve their structures to 200 and 250 °C, respectively, and remain stable in polar organic solvents and a wide range of pH solutions. Under visible-light irradiation, CO2 can be converted into syngas and HCOO- with V12B18-Co or V12B18-Ni as catalysts. The total amount of gaseous products and liquid products for V12B18-Co is up to 9.5 and 0.168 mmol g-1 h-1. Comparing with V12B18-Co, the yield of CO for V12B18-Ni declines by 1.8-fold, while that of HCOO- increases by 35%. The AQY of V12B18-Co and V12B18-Ni is 1.1% and 0.93%, respectively. These values are higher than most of the reported POM materials under similar conditions. The density functional theory (DFT) calculations illuminate the active site of CO2RR and the reduction mechanism. This work provides new insights into the design of stable, high-performance, and low-cost photocatalysts for CO2 reduction.

The rubber tree (Hevea brasiliensis) is an economically important source of natural rubber. H. brasiliensis grows slowly in southern China mainly because of relatively low temperatures there. The slow growth rate delays plant propagation, so ways of increasing growth are needed. Light is important for regulating plant growth. An extended photophase is commonly used to increase plant growth and development. We studied the effects of an extended photophase, by supplemental LED night lighting, on the growth and physiology of young H. brasiliensis. Night lighting significantly increased plant height, stem diameter, and flush number. Chlorophyll a and total chlorophyll contents significantly increased, while chlorophyll b and carotenoids were unaffected. The photosynthetic parameters, nutrition status, and soluble sugar and protein contents changed little with supplemental lighting. The activities of antioxidases, including superoxide dismutase, peroxidase, and catalase, were similar in the experimental and control plants. The results showed that overnight LED lighting, in addition to solar irradiation during the daytime, could improve the rhythmic growth of H. brasiliensis without causing obvious physiological changes.

Direct conversion of diluted CO

The synthesis of ultra-stable chiral porous organic cages (POCs) and their controllable chiral self-sorting at the molecular and supramolecular level remains challening. Herein, we report the design and synthesis of a serial of axially chiral porous aromatic cages (PAC 1-S and 1-R) with high chemical stability. The theoretical and experimental studies on the chiral self-sorting reveal that the exclusive self-recognition on cage formation is an enthalpy-driven process while the chiral narcissistic and self-sorting on supramolecular assembly of racemic cages can be precisely regulated by π–π and C–H…π interactions from different solvents. Regarding the chemical stability, the crystallinity of PAC 1 is maintained in aqueous solvents, such as boiling water, high-concentrated acid and alkali; mixtures of solvents, such as 1 M H2SO4/MeOH/H2O solution, are also tolerated. Investigations on the chiral sensing performance show that PAC 1 enables enantioselective recognition of axially chiral biaryl molecules.

A TPE-based fluorescent porous covalent organic polymer (COP-3) was designed and synthesized. The COP-3 exhibits excellent performance in sensing Fe3+ with high anti-interference, recyclability and a low limit of detection (LOD) of 0.191 μM (10.696 ppb), which is much lower than those of the reported metal-free porous polymers.

The reversible thermochromic luminescence and rare third-order NLO properties of the {Ag55Mo6} nanocluster reported were studied experimentally, and the contributions of Ag+, CC− and MoO42− groups to NLO properties were proved by DFT calculations.

Two new zirconium-based heterometal–organic frameworks, Zr3CP3–Mn (1) and Zr3CP3–Ni (2), constructed from [Cp3Zr3(μ3-O)(μ2-OH)3(IN)3] secondary building units and transition metal cations, were successfully synthesized through a one-pot method. Single-crystal X-ray diffraction analysis shows that both 1 and 2 have one-dimensional chain structures, in which [Cp3Zr3(μ3-O)(μ2-OH)3(IN)3] SBUs are connected by Mn and Ni ions. Furthermore, photoreduction of CO2 under visible light irradiation reveals that 1 and 2 have good catalytic activities to reduce CO2 into carbon monoxide and hydrogen. The CO yields of 1 and 2 were 9.30 and 5.21 mmol g−1 h−1 under one hour irradiation at 293 K, respectively. In addition, the inherent photocatalytic mechanism was studied through photochemical and electrochemical measurements. This work provides a valuable perspective for the design and synthesis of simple, low-cost MOF catalysts for photoreduction of CO2.

An unprecedented Mo-organic molecular cage built on interesting {MoVI2O5} secondary building blocks and BTC ligands, which has been successfully synthesized and systematically characterized, presents the first example of an isopolyoxomolybdates(vi)-organic molecular cage. An investigation into the related Cs+-exchange experiment was performed in detail.

Ferroelectricity has an excellent reversible polarization conversion behavior under an external electric field. Herein, we propose an interesting strategy to alleviate the shuttle effect of lithium-sulfur battery by utilizing ferroelectric metal-organic framework (FMOF) as a host material for the first time. Compared to other MOF with same structure but without ferroelectricity and commercial carbon black, the cathode based on FMOF exhibits a low capacity decay and high cycling stability. These results demonstrate that the polarization switching behaviors of FMOF under the discharge voltage of lithium-sulfur battery can effectively trap polysulfides by polar-polar interactions, decrease polysulfides shuttle and improve the electrochemical performance of lithium-sulfur battery.

Systematic design and self-assembly of metal-organic polyhedra with predictable configuration has been a long-standing challenge in crystal engineering due to the difficulty of finding suitable building units. Herein, we are focused on a concave polyoxovanadate cluster [V6O6(OCH3)9(SO4)4]5- that can be generated in situ under the exact reaction conditions. Based on this cluster, a potential trivalent molecular building block [V6O6(OCH3)9(SO4)(CO2)3]2- can be obtained by the bridging-ligand-substitution strategy that possesses appropriate angle information for the design of molecular cubes. Utilizing the face-directed assembly of the trivalent molecular building block and a diverse set of tetratopic carboxylate linkers, a series of metal-organic cubes VMOC-1 to VMOC-5 with the same topology but different functionalities and dimensions are designed and constructed. The inclusion study made with VMOC-3 as an example has shown that they are potential molecular receptors and can selectively capture size-matching polycyclic aromatic hydrocarbon guest molecules.

The lithium-sulfur battery is a promising high-energy-density storage system, which suffers from severe capacity fading due to the "shuttle effect" and low Coulombic efficiency caused by the dissolution of lithium polysulfides. At the molecular level, suppressing the shuttle effect has been greatly required for high-performance Li-S batteries. Herein, we propose a new strategy by utilizing a protonated organic absorbent (N1,N4-bis(pyridine-3-ylmethyl)butane-1,4-diammonium nitrate ([H2PBD]2+·(NO3)22-) for ultrafast absorption of polysulfides through electrostatic attractions and for fixing the polysulfides in the cathode by hydrogen-bond interactions. A lithium-sulfur battery cathode based on a commercial carbon black (CB) and an absorbent (10%) with high sulfur content (70%) exhibits a low capacity decay of 0.099% per cycle over 400 cycles at a rate of 0.5C along with 91% Coulombic efficiency. This strategy and the finding of an electrostatic absorbent offer a new alternative insight into designing cheaper lithium-sulfur batteries for their practical application in the future.

For high reactivity but poor stability of homogeneous metal complexes in CO2 photoreduction, development of durable systems is still a big challenge. Herein, pentanuclear Co(II) complex [Co5(btz)6(NO3)4(H2O)4] (1, btz = benzotriazolate) is explored for converting CO2 to syngas which shows high stability and reactivity in both pure and diluted CO2. Compared with mononuclear structure, multinuclear complex exhibits 212-fold enhancement in reactivity, up to ~2748 TONs, with wide adjustability of H2/CO ratio from 16:1 to 2:1. This reactivity could be maintained over 200 h which is an order of magnitude higher than the durability of mononuclear complex and exceeds most reported homogeneous molecular catalysts. High reactivity is also achieved in extreme low CO2 content (5%). Structural analysis and density functional theory (DFT) calculations support that multinuclear structure and the low energy barrier for photocatalytic intermediate may account for the durable and efficient performance of complex 1. The multinuclear strategy is also adopted to nickel complex. This work probes origin of metal-node-dependent performance for CO2 photoreduction, providing new insights in design of durable and efficient metal complexes for photocatalysis and other applications.

The direct usage of CO

Fully reduced polyoxometalates are predicted to give rise to a broad and strong absorption spectrum, suitable energy levels, and unparalleled electronic and optical properties. However, they are not available to date. Here, an unprecedented fully reduced polyoxomolybdate cluster, namely Na

At present, the fixation of CO2 always requires it to be extracted from the atmosphere first, which leads to more energy consumption. Thus, direct photoreduction of low-concentration CO2 to useful chemicals (e.g., syngas) under sunlight is significant from an energy-saving and environmentally friendly perspective. Here, the design and fabrication of a [Ru(bpy)3 ]/[Co20 Mo16 P24 ] composite is demonstrated for visible-light-driven syngas production from diluted CO2 (3-20 %) gas with a high yield of approximately 1000 TONs (turnover number of syngas). This activity is an order of magnitude higher than the reported system with [Ru(bpy)3 ]2+ participation. With evidence from ultrafast transient absorption, GC-MS, 1 H NMR spectroscopy and in situ transient photovoltage tests, a clear and fundamental understanding of the highly efficient photoreduction of CO2 by the [Ru(bpy)3 ]/[Co20 Mo16 P24 ] composite is achieved. Making use of the structure and property designable polyoxometalates towards the photo-fixation of CO2 is a conceptually distinct and commercially interesting strategy for making useful chemicals and environmental protection.

Root trainers are increasingly being used to avoid root coiling and distortion and lack of wind tolerance after field transplanting, when compared to the conventional polybag planting system. Root tips grew out of root trainer forming an intact root mass and then could be transplanted to the field with high survival rate. While the influence of spatial position on root tips growing out of budded stump root trainer was still unknown at nursery stage. Therefore, the bottoms of root trainer were placed in aboveground(20cm, current practice), touchdown(0cm) and underground(15cm) for budded stump nursery, respectively. Clone CATAS 7-20-59 budded stump was raised in root trainer and percentage of plants with root tips outgrowing, growth performance, leaf N content, leaf SPAD, leaf temperature and leaf surface humility were recorded, respectively. The results showed that root trainer touchdown of budded stump gave more percentage in root tips growing out of root trainer, more leaf N content(P

The development of metal complexes for optoelectronic applications is a fertile area of research. In contrast to the rigorous development of mononuclear metal complexes, dinuclear species have been less well studied and their fundamental chemistry and applications are under-explored. However, dinuclear species present special properties and functions compared with mononuclear species as a consequence of tuning the bridging ligands, the cyclometalated ligands or the two metal centers. More recently, dinuclear species have enabled important breakthroughs in the fields of OLEDs, photocatalytic water splitting and CO2 reduction, DSPEC, chemosensors, biosensors, PDT, smart materials and so on. Here we present an overview of recent developments of dinuclear metal complexes, their multifunctional properties and their various applications. The relationship between structure and property of dinuclear species and important factors which influence device performance are discussed. Finally, we illustrate some challenges and opportunities for future research into dinuclear metal complexes. This review aims to provide an up-to-date summary and outlook of functional dinuclear metal complexes and to stimulate more researchers to contribute to this exciting interdisciplinary field.

Light irradiation can affect electronic properties of catalysts and the introduction of appropriate light into electrocatalysts may have a significant impact on the electrocatalytic process; however, this has not been fully studied. Herein, we propose a photo-activated process cascaded electrocatalysis for CO2 reduction to produce syngas over a core–shell ZIF-8@Co/C catalyst. Under light irradiation, the onset potential and overpotential of ZIF-8@Co/C positively shift by 40 and 200 mV, and the syngas production is enhanced 5.2-fold at a bias potential of −0.9 V vs. RHE. It is noteworthy that the electric energy efficiency is enhanced by 30%. Deducting syngas generated by electricity, the solar-to-syngas conversion efficiency (joule to joule) is as high as 5.38%, which outperforms reported photoelectrochemical systems. These devices also relatively maintain high efficiency in neutral pH aqueous solution. Dedicated experiments and in situ transient photovoltage studies demonstrate that the cascaded photo-activation of CO2 and H+ in electrocatalysis accounts for the outstanding catalytic performance.

Direct CO2 conversion from flue gas into high-value products is of great significance not only in relieving environmental burden but alleviating the energy crisis by a low-cost and energy-saving avenue, yet few studies in this aspect have been reported. Herein, we report metal-node-dependent catalytic performance for solar-energy-powered CO2 reduction to formate in simulated flue gas by bimetallic Ni/Mg-MOF-74. The yield of HCOO− with Ni0.75Mg0.25-MOF-74 as a catalyst in pure CO2 is 0.64 mmol h−1 gMOF−1 which is higher than that of Ni-MOF-74 (0.29 mmol h−1 gMOF−1) and Ni0.87Mg0.13-MOF-74 (0.54 mmol h−1 gMOF−1), whereas monometallic Mg-MOF-74 is almost inactive, indicating that reactivity relies on metal nodes. In simulated flue gas without water vapor at 20 °C, ∼80% of the reactivity in pure CO2 is retained, with HCOO− generation reaching 0.52 mmol h−1 gMOF−1. This activity is comparable to that of the best MOF catalysts in pure CO2, demonstrating that Ni/Mg-MOF-74 not only overcomes the limitation from CO2 concentration, but also has good resistance to other gas components in flue gas at 20 °C. DFT calculations reveal the high output for HCOO− from two crucial factors: strong CO2 binding affinity of Mg sites, and the synergistic effect of Mg and Ni leading to the stabilization of the key *OCOH intermediate with an appropriate energy barrier. This work paves a new route for double-metal MOFs to enhance the CO2 photoreduction reactivity in flue gas.

We prepare a novel COF for CO2 photoreduction with 99.9% CO selectivity in aqueous solution without a cocatalyst. DFT shows that the preferential adsorption of H+ on the COF results in increased CO2 adsorption energy providing an anchoring site of CO2, and with the cooperation of an ethylene group, CO2 reduction is triggered.

Multi-component tungsten carbide-based hybrid materials featuring different heteroatom dopants coated with X,N dual-doped carbon layers (X/W2 C@X,N-C, XWXNC) were prepared by selecting Keggin-type polyoxometalates (POMs) (NH4 )n [XW12 O40 ] (X=Co, Si, Ge, B, and P) and dicyandiamide (DCA) as precursors. The electrocatalytic activity of these nanocomposites as counter electrode (CE) catalysts for dye-sensitized solar cells (DSSCs) was systematically investigated. Structure characterizations show that X,N heteroatoms were successfully introduced into the W2 C and carbon frameworks. The obtained X,N dual-doped carbon layers were modified and loaded with W2 C nanoparticles, promoting the improvement of catalytic performance by a synergistic effect. The consequence of photoelectric conversion efficiency (PCE) is CoWCoNC (6.68 %)>SiWSiNC (6.56 %)>GeWGeNC (6.49 %)>BWBNC (6.45 %)>PWPNC (6.20 %)>WNC (6.05 %). With the increase in electronegativity of the dopants, the photovoltaic performance decreases in a reverse order. This work provides a shortcut to the rational design of highly efficient and cost-effective catalysts for DSSCs.

A new supramolecular nanocage, VMOP-31, based on polyoxovanadate as the molecular building block, has been designed and synthesized under solvothermal conditions. The structure of VMOP-31 was determined by single-crystal and powder X-ray diffraction, FTIR spectroscopy, UV/Vis spectrophotometry, and thermogravimetric analysis. The nanocage exhibits octahedral geometry and is constructed of six {V5 O9 Cl(COO)4 } at the vertices and eight TATB (H3 TATB=4,4',4''-(s-triazine-2,4,6-triyl)tribenzoic acid) ligands on the faces. Impressively, VMOP-31 exhibited high efficiency in the inhibition of cell growth of solid tumors, such as human liver cancer cells SMMC-7721, and superior results in the treatment of liver tumors in mice compared with classic cisplatin. Detailed studies revealed that the potential mechanism of cell death induced by VMOP-31 involves cell cycle arrests, DNA damage, and subsequent apoptosis. Moreover, VMOP-31 exhibited negligible side effects in the mice compared with cisplatin. To the best of our knowledge, VMOP-31 is the first supramolecular nanocage applied to hepatic tumors both in vitro and in vivo.

Three nanoscale Nb/W mixed-addendum polyoxometalates, Cs14K4[(Si4W36Nb12O156)Cu(H2O)2]·47H2O, Cs10K8[(Si4W36Nb12O156)Zn(H2O)2]·28H2O, and Cs16[(H2Si4W36Nb12O156)Cd(H2O)2]·75H2O involving [SiNb3W9O40]7− fundamental building unit, have been synthesized, which all show photocatalytic hydrogen evolution activities. Furthermore, molecules 1, 2, and 3 are stable in the photocatalytic hydrogen evolution system. The embedding transition-metal cations into Nb/W mixed-addendum POMs can improve the photocatalytic H2 evolution activity.

A sailing ship can produce significant disturbances on the water surface, but the perturbation generated by a moving submerged source is much smaller due to the physical property of the free surface, as represented by the rigid-lid assumption, with the geometric displacement barely observed or measured. Based on the stereo imaging principle, an experimental system for the three-dimensional measurement of the surface perturbation is built by assembling two charge coupled device (CCD) sensors, to measure the surface waves generated by a small submerged sphere, including the small-scale vertical displacements and the flow field on the water surface. The obtained results are consistent with those obtained by the theoretical analysis, and the measurement accuracy for the vertical displacements is improved by 50% compared to that of the direct optical method based on the image grey levels. Additionally, the present measurement technique can be efficiently and precisely applied to other measurements of small-scale disturbances on a free surface.

A novel porous triazine-based metal-organic framework, ([Cd (Ligand)]∙2DMF) (1) with strong luminescence, has been constructed via multi-carboxyl ligand 5,5′,5''-((1,3,5-triazine-2,4,6-triyl)tris(azanediyl))tris(3-methylbenzoic acid) under solvothermal conditions. Structural analysis revealed that MOF1 has a three-dimensional (3D) framework which is crystallized in the monoclinic system bearingC2/c space group. The high chemical and thermal stability of synthesized MOF1 has been predicted by powder X-ray diffraction and thermogravimetric analysis techniques. Higher selectivity and sensitivity of MOF1 towards Cu2+ions is remarkable with an adsorption capacity of 90.5 mg/g compared with Mg2+, Mn2+, Ni2+, Co2+, Zn2+, Fe2+ and Cr3+ ions. Results reveal that strong emission of MOF1 can be quenched effectively by a trace amount of copper (3 ppm) and nitrobenzene (0.6 ppm), even in the vapor phase. The extraordinary solvatochromic phenomenon of MOF1 is observed by incorporating acetonitrile guest molecules due to host-guest interactions provided by the carboxyl groups of ligand and imino triazine backbone. Thus, owing to the highly selective and sensitive quenching effect in fluorescence and solvatochromic behavior, MOF1 can be used as a potential sensor for Cu2+, NB, and acetonitrile.

The remarkably reversible thermochromic luminescence behavior and the rare nonlinear optical (NLO) properties of the [Ag

The stable hydrogen generation catalysts with favorable performance have been widely studied. As we all know, bimetallic hybrids have been emerged as one type of outstanding electrocatalysts and applied to electrochemical hydrogen generation field. In this work, using bimetallic polyoxometalates (POM) as soft templates and polyethyleneimine (PEI) as carbon source, we synthesized cobalt and tungsten-based bimetallic electrocatalysts (Co/WC@NC) via one-step simple high temperature calcination process.Co/WC@NCexhibits good hydrogen evolution performances. Thereinto, the overpotentials are 129 and 142 mV at the current density of 10 mA cm-2, and the Tafel slopes are 93 and 91 mV dec-1in 0.5 M H2SO4and 1.0 M KOH aqueous solutions, respectively. Furthermore, the catalyst shows good stability for 24 h. The excellent catalytic performance (Co/WC@NC) can be ascribed to the synergistic effect of WC and Co nanoparticles and the protection function of graphitic carbon layers. Furthermore, this work may provide an experimental guidance for the large-scale production of low-cost materials with good catalytic effects.

Photocatalytic carbon dioxide reduction (CO